In the past, in order to perform measurement control of production equipment, an industrial controller including a programmable controller (to be referred to as a “PC” hereinafter) is used. As a measurement control program executed in an industrial controller, a language being in compliant with IEC61131-3 typified by a ladder program or a controller-specialized language is given. In place of the industrial controller, as a measurement control program in use of a microcomputer, C language or Assembler is given. The following description will be made while using a PC as an example.
A PC executes a ladder program serving as measurement control program to recognize a state of a measurement control subject or to designate a measurement control subject to operate. In creation of a ladder program, a predetermined measurement control program creation support device (ladder creation support device) is used. The measurement control program creation support device is generally provided as a software tool operated in a personal computer and has a function of supporting editing of a ladder serving as a program used when a PC measures or controls a measurement control subject. In addition, the measurement control program creation support device has a function of connecting a personal computer to a PC to transfer the edited ladder to the PC and a function of monitoring a state of a value of a variable (to be referred to as a “device” hereinafter) changed depending on a state of the measurement control subject or execution of the ladder. The program editing function and the monitoring function provided by the measurement control program creation support device) are also mounted on a display (to be referred to as a “GOT” hereinafter). Also on the GOT that is always connected to the PC, editing of the measurement control program or monitoring of the state of the value of the device can be performed.
When the scale of production equipment is very small, the measurement control program is sufficiently configured by one ladder program. However, in general, a program to measurement control production equipment is configured by a plurality of program modules (to be referred to as a “POU” (Program Organization Unit). When a program language of the measurement control program is a ladder language, the POU corresponds to a subroutine or an FB (Function Block). When the program language is an ST (Structured Text) or C language, the POU corresponds to a subroutine or a function.
In this case, a large number of devices that are commonly measured and controlled between different POUs are present. Therefore, in analysis of a range influenced by a change and an upgrade of a program or analysis or the like of a cause of a drawback operation, a POU in which a certain device is used and a position where the certain device is used (position where reading is performed/position where writing is performed) need to be known. In order to improve the efficiency of the operation, there is necessity of rapidly specifying a use place of a device in the program (in the POU). Therefore, as a program analysis support device to specify the place, a cross-reference creating device is known. The cross-reference creating device is a device that reads a plurality of POUs as analysis results to form a list of positions and POUs in which a certain device is used or form a list of all devices used in a certain POU. Creation of such a cross-reference may be realized as one function of a measurement control program creation support device.
In an instruction in Non-patent Document 1, two conventional techniques are disclosed. The conventional techniques will be described below.
In the first conventional technique, a cross-reference function that forms a list of POUs where a certain device is used and positions of the POUs where the certain device is used is realized as one function of a measurement control program creation support device. When the cross-reference function is selected from a menu of the measurement control program creation support device, a dialog serving as a cross-reference screen is displayed on a screen. First, in a device column of the dialog, an operator inputs a device. Then, the operator designates a searching range in a searching range column of the dialog. At this time, the operator may designate all POUs as the searching range, or may designate only a specific POU as a searching range. Thereafter, when operator clicks an execution button displayed on the dialog, a list of POUs where the device is used and positions where the device is used is displayed on the dialog. In a program name column on the dialog, the name of a POU is displayed, and in a sequence step column, a step number in which the device is used in the POU is displayed. Furthermore, in an instruction column on the dialog, a type of an instruction of the step in which the device is used is displayed. For example, the program (POU) is described in a ladder language, a contact, or a coil, or the like is displayed in the instruction column.
In the second conventional technique, a list (device use list) of devices used in a certain POU is formed on a screen. This list forming function, in the second conventional technique, is realized as a function of a measurement control program creation support device. When an operator selects a printing function from a menu of the measurement control program creation support device, a dialog to display a device use list is displayed on a screen. First, the operator selects a program. That is, the operator inputs a name of a POU to be selected in a program selecting column displayed on the dialog. The operator designates a printing condition displayed on the dialog. At this time, when only a device used in the program is printed as a list, the operator inputs a designation for check in the column. When the designation for check is not input, all devices are printed as a list. In this state, when the operator clicks a print button displayed on the dialog, a list of devices used in the POU is printed. The name of the selected POU is printed on the program name column. Under the name, the devices used in the POU are sequentially printed. In a use/nonuse column, a type of an instruction in which the device is used is printed. When the program is described in a ladder language, a contact, a coil, or the like is printed. When the device is used as a contact and a coil in the POU, both the contact and the coil are printed.